On Thu, 27 Aug 2020 at 09:50, Alexandre Courbot <gnurou@xxxxxxxxx> wrote:
>
> Factorize redundant checks into a single code block, remove unneeded
> checks (a buffer in done_list is necessarily in the DONE or ERROR
> state), and we end up with a much simpler version of this function.
>
> Signed-off-by: Alexandre Courbot <gnurou@xxxxxxxxx>
This is really good, thanks!
Reviewed-by: Ezequiel Garcia <ezequiel@xxxxxxxxxxxxx>
> ---
> drivers/media/v4l2-core/v4l2-mem2mem.c | 26 +++++---------------------
> 1 file changed, 5 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c
> index fe90c3c0e4128..af8138c5d7ced 100644
> --- a/drivers/media/v4l2-core/v4l2-mem2mem.c
> +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c
> @@ -841,7 +841,6 @@ static __poll_t v4l2_m2m_poll_for_data(struct file *file,
> struct poll_table_struct *wait)
> {
> struct vb2_queue *src_q, *dst_q;
> - struct vb2_buffer *src_vb = NULL, *dst_vb = NULL;
> __poll_t rc = 0;
> unsigned long flags;
>
> @@ -862,32 +861,17 @@ static __poll_t v4l2_m2m_poll_for_data(struct file *file,
> list_empty(&dst_q->queued_list)))
> return EPOLLERR;
>
> - spin_lock_irqsave(&dst_q->done_lock, flags);
> - if (list_empty(&dst_q->done_list)) {
> - /*
> - * If the last buffer was dequeued from the capture queue,
> - * return immediately. DQBUF will return -EPIPE.
> - */
> - if (dst_q->last_buffer_dequeued)
> - rc |= EPOLLIN | EPOLLRDNORM;
> - }
> - spin_unlock_irqrestore(&dst_q->done_lock, flags);
> -
> spin_lock_irqsave(&src_q->done_lock, flags);
> if (!list_empty(&src_q->done_list))
> - src_vb = list_first_entry(&src_q->done_list, struct vb2_buffer,
> - done_entry);
> - if (src_vb && (src_vb->state == VB2_BUF_STATE_DONE
> - || src_vb->state == VB2_BUF_STATE_ERROR))
> rc |= EPOLLOUT | EPOLLWRNORM;
> spin_unlock_irqrestore(&src_q->done_lock, flags);
>
> spin_lock_irqsave(&dst_q->done_lock, flags);
> - if (!list_empty(&dst_q->done_list))
> - dst_vb = list_first_entry(&dst_q->done_list, struct vb2_buffer,
> - done_entry);
> - if (dst_vb && (dst_vb->state == VB2_BUF_STATE_DONE
> - || dst_vb->state == VB2_BUF_STATE_ERROR))
> + /*
> + * If the last buffer was dequeued from the capture queue, signal
> + * userspace. DQBUF(CAPTURE) will return -EPIPE.
> + */
> + if (!list_empty(&dst_q->done_list) || dst_q->last_buffer_dequeued)
> rc |= EPOLLIN | EPOLLRDNORM;
> spin_unlock_irqrestore(&dst_q->done_lock, flags);
>
> --
> 2.28.0
>
